When building or managing a website, you may encounter the term "memory limit". This refers to the maximum amount of RAM (Random Access Memory) that a script or application on your hosting account is allowed to use at one time. It's a crucial resource control set by hosting providers to ensure server stability and fair usage among all customers.

Exceeding this limit typically results in a fatal error, often displayed as: "Fatal error: Allowed memory size of X bytes exhausted". This means your script tried to use more memory than was permitted.

Common causes include:

• Inefficient code: Loops that don't end or load too much data at once.
• Large plugins/themes: Some WordPress or other CMS add-ons are memory-intensive.
• High traffic: More simultaneous visitors can increase memory usage.

To manage memory limits:

1. Check your current limit through your hosting control panel or a phpinfo() file.
2. Optimize your website by updating software, using caching, and removing unused plugins.
3. Contact support to inquire about increasing your limit if optimization isn't sufficient. Higher-tier hosting plans usually offer more resources.

Understanding and monitoring your memory usage is key to maintaining a fast, reliable website and avoiding unexpected downtime.